Apparatus for drying webs of material, especially stentering machines



Jan, 3, 3950 K. s. LAURIE 2,493,253

APPARATUS FOR DRYING WEBS 0F MATERIAL, ESPECIALLY STENTERING MACHINES 4 Sheets-Sheet 1 Filed March 15, 1946 Q Rn Mn M w T N: R E O vm I mw M w m .u a m M M Q h fi .3 JU w fi Jan. 3, 11950 K. s. LAURIE 2,493,253

APPARATUS FOR DRYING WEBS OF MATERIAL, ESPECIALLY STENTERING MACHINES Filed March 13, 1946 4 Sheets-Sheet 2 Arr Ls Jan. 3, 1950 K. s. LAURlE 2,493,253

APPARATUS FOR DRYING WEBS OF MATERIAL, ESPECIALLY STENTERING MACHINES Filed March 13, 1946 4 Sheets-Sheet s K. S. LAURIE Jan. 3, I950 APPARATUS FOR DRYING WEBS OF MATERIAL, ESPECIALLY STENTERING MACHINES 4 Sheets-Sheet 4 Filed March 15, 1946 W m m 2%. V/ M M a w V/ V w rmw vm Patented Jan. 3, 1950 APPARATUS FOR DRYING WEBS' F MATERIEL, ESPECI MACHINES:

STENTERING" Kenneth Somerville Laurie,a Glasgow,- Scotland; assi'gnor to. J ohn 'Dlflglish, Glasgow; Scotland ApplicationtMarchln, 1946, Serial No. 654,169

In Great Beitain March, 1945 This invention relates. to. machines for. dryin webs. of material such. as.fabric.,.paper. or the like, especially clothstentering machines.

In such machines it has been the practice hitherto to effect. drying. by blowing. heated -wir in jets on to the upper and lower surfaces eithefabric. or the like during. its. conveyance through the. machine. and: a large. proportion of the. air leaving the. fabric is. recirculated: and. reheated and blown againionato thefabric. a

In apparatus as. hitherto: pr.oposed,. there? has been: a tendency tov require: an expenditure of: a relatively: large. amount. ofi power in. circulatin the. heated air, owing. to: the; frictional losses on the walls: of the conduits in passage-of the air: through. relatively small; spaces,- in-a turbulence: 02 theair: generated. by: generally non-streamlined airflow; and in: heat lossesby condiictimrtorthe external atmosphere;

Moreover; unless the dryingoff'a web is uniiomr throughout its width, itis necessary to cverdry some-parts inordcr todr-y' other parts suflicientiy-g and this may cause damage to the web onmay:

necessitate subsequent dampening; alternatively the webis left with some partsnot sufficiently dry: These-factors may have'a badwfiect cn 'sub sequent'treatmentof-the web; especially in textile" finishingprocesses.

One of the chief objects of the presentlnvenation is to provide a drying machine in whichthe velocity of the air is. kept aslowas'possibleinr the passages, and circulation of the air learranged so as to. provide low resistance with as. relatively low degree ofturbulenceandrelatively Figure 1 is a planview Ofi the machine-withing top of. the casingiremoved' for; cleamess;. intermediate parts of the machine.being hmkeniawayt Figures 2 andz2a show a side elevation. Figure 3 is a cross sectional v-iewron the line III--III of. Figure 1, to a difierentscalel Figure 4 is a detail diagrammaticview' of air nozzles,- to an enlarged scale.

Figure 5 isa vertical section on. the-line V- fl Figure 3'. l

5 Claims. (Cl. 84

In the machine the web 5of cloth to be dried carried. along longitudinally in the machine between two longitudinal opposed stenter guide rails 6' (shown diagrammatically in Figure 3"), said. rails carrying in the usual way chains and cloth grippers. For heat insulation purposes the whole machine is enclosed in a casing comprising heatiinsulating panels T at each side and similar panels 8 at the top and end'panels, all saidpanels being secured to an open framework 9 of angle pieces. S'aidpanels may be made, for example, ofcorK-lined sheet metal; andsame maybe easily removable for access to: parts. of the machine;

The web" is carried through the machine on its guide rails 6 by a m.echanical drive It le din from driving mechanism of known construction, and the web enters the machine. casing at H at one en'diandleaves at the other end at" lla; there being. spaces atsuch' ends above. and below the cloth.

'V fithi'n the casing: is a central. longitudinal air delivery'chamberor conduit. I'Z', said conduitbeing' duplicated, having" one part above the' web and the other part below; asshown'in'Figure 3. N02

' zlesl l'direct' drylngair from'i'nsi'dethe upper and lower delivery conduits; blowing samedirectiyon to; the cloth Web;

The outer sidewalls of the machine" casing form return air conduits l3; one' on each sideo'f the central delivery conduits; conduits" l 2 and [3" each being? separated from each other by longi' tudinal' partitions or walls2'3i 2"4, alsosupport'ed on angle piece framing. The parts'2'3aa'nd 24b of said walls; that is, the partsin line with the guide rails" 6, are" provided. onlyin the region of thei'airdeliveryians I 4" (see'Figure 5') and extend" over approximately" the width between two' air heaters I 5; l5a' (Fig; I) ineach case; these" parts 23h; 24lrthus ensure" that'the' air' cannot bypass the heaters; The rest of the partition walls- 23; 24 are'continuous andleave'iong"portsinline the guide railsand communicating betweenthe web space and the 'returnconduits':

The biowersorfans'shownby way of example at'lfl are ofaxialilow type'having" blades IB-and a-streaml-ined fairing (9'; Each fan is driven by an electric motor H; and the air is delivered througlra 'd'ifiuser I6 (one-only of-whichis shown by" way of" example in'Flg. 1 the saiddifihser having internal dividing partitions I611.

The diffusers lfitoget'her withthe airings 19 provide a Vent-uri-shapedfieliveryoutlet; the=dif fuser= diverging from circular formationto rectangul'ar format-ion at it's :outlet.

It will be seen that the air delivered from the d-ifiuser ifito:thedeliverycondui-t l2 -passes-dowm from the upper' conduit and up from the lower conduit and threugh nozzlesfl and on to the web i irom tonand' bottom and flows over the'whclc 3 upper and lower surfaces thereof. The air then escapes transversely and the blocking effect of the guide rails 6 is overcome by the shape of the nozzles as shown in Fig. 4 (as hereinafter explained). The air then passes through into the return conduits l3 and returns towards each electric motor from each branch (left hand and right hand) as will be seen in Fig. 1, passing through two heaters 15 and [5a one ineach branch, and it is re-circulated again through the fans at top and bottom.

The same circulation occurs at each pair of 4. square of the speed and this arrangement is therefore successful in reducing air resistance losses. the heaters thus operating in parallel and not in series.

fans, and although two pairs only are shown in Figs. 1 and 2, there may be any number of intermediate pairs in accordance with the length of the machine.

The general circulation of the air throughout the machine is shown by the arrows, the passage of air from the cloth space between the nozzles out to the return conduits being indicated by dotted arrows in Fig. 1.

Furthermore, in a short machine there may only be one pair of fans located about the middle of the machine.

The electric motors l! are automatically cooled by mounting the motors on spiders 22, and an annular clearance is provided at 2! whereby cooling air is drawn throughapertures in the outer casing l as indicated by the arrows and is delivered into the main air system via the suction side of the fans.

As shown in Figure 4 the nozzles are formed by juxtaposing a series of channel plates 34 having parallel inclined side flanges, the spacing between the flanges of adjacent channels forming a parallel-sided nozzle 25 through which the air is delivered. The spaces 26 between the flanges of each channel provide passages through which the air can by-pass over and under the guide rails 6 thereby avoiding any constriction in the air passage. The nozzles may be arranged spaced four inches apart and may be of the width of 4 inch, while the channels may be two inches deep. The channels may be supported on the framing supporting walls 23, 24 and they thus form horizontal walls of the conduits l2, with a series of nozzles 25 therein.

The axial flow propeller fans are preferably operated so as to build up a static air pressure in the delivery conduit of say or inch of water. The arrangement of the fans as described ensures that a substantially positive pressure exists all along the delivery conduits, so that uniform amounts of air are delivered through all the nozzles throughout the length of the machine.

The major part of the air in the machine is recirculated, but apart from cooling air entering at the fans, an additional amount of fresh air enters the machine at the ends II and Ila, and the total amount of fresh air entering may amount to only about five per cent of the air being circulated, a corresponding amount of moist air being exhausted through suitable exhaust apertures not shown.

Centrifugal fans or other blowers may of course be used instead of the axial flow fans.

By causing the return air flow to each of the fans to take place through two branches (on the left hand and right hand of the fan, see Fig. 1) and by splitting the total heating required at each fan into two heaters I5, 1511, the required speed of air delivery for a given degree of drying is halved. The resistance to air flow isproportional to the The important portions of the air circuit and of the stenter, such as the air heaters, stenter rails, air nozzles and fans, are all accessible and easily dismountable and so can be easily kept clean and maintained. The air circulation circuit two inner air delivery conduits extending longitudinally one above and one below the web, two air return conduits extending longitudinally one on one outer side and the other on the other outer side of said delivery conduits, outer heat insulating conduit walls which enclose all said delivery and return conduits and define said delivery conduits, and longitudinal partition walls separating the return conduits from the delivery conduits and defining the return conduits, an electric motor and air delivery fan disposed transversely in the upper part of one return conduit and circulating air into the upper delivery conduit for delivery downwardly on to the top of the web and back over the web selvedge adjacent thereto, an electric motor and air delivery fan disposed transversely in the lower part of the other return conduit and circulating air into the lower delivery conduit for delivery upwardly onto the underside of the web and back across the web selvedge adjacent thereto, air heaters disposed longitudinally of said fans and on each side thereof in the respective return conduits, air passages through said partition walls adjacent the respective heaters allowing the air to pass from the web back through the heaters on each side of each fan for delivery to the delivery conduits, a series of air nozzles on the bottom of the upper delivery conduit and the top of the lower delivery conduit for blowing the air on to the web, said nozzles being formed as transverse slots extending over the maximum width between the stenter guide rails and including side walls defining said nozzles and extending towards the web at an inclination thereto and leaving between the side walls transverse air escape channels extending widthwise over the guide rails at the maximum width spacing thereof.

' 2. A machine for air drying a web of material, including longitudinally extending stenter guide rails the width spacing between which is adjustable and between which the web is progressed through the machine; comprising in combination two large inner air delivery conduits extending longitudinally one above and one below the web, two large air return conduits extending longitudinally one On one outer side and the other on the other outer side of said delivery conduits, outer heat insulating conduit walls which enclose all said delivery and return conduits and define said delivery conduits, and longitudinal partition walls separating the return conduits from the delivery conduits and defining the return conduits, an electric motor and air delivery fan disposed transversely in the upper part of one return conduit and circulating air into the upper delivery conduit for delivery downwardly on to the top of the web and back over the web selvedge adjacent thereto, an electric motor and air delivery fan disposed transversely in the lower part of the other return conduit and circulating air into the lower delivery conduit for delivery upwardly onto the underside of the web and back across the web selvedge adjacent thereto, an axial streamlined fairing at the delivery side of each fan, a divergent diifuser surrounding the side walls of said fairing, said diifuser and fairing forming a Venturi-shaped outlet for the air from the fan air f heaters disposed longitudinally of said fans and on each side thereof in the respective return conduits, air passages through said partition walls adjacent the respective heaters allowing the air to pass from the web back through the heaters on each side of each fan for delivery to the delivery conduits, a series of air nozzles on the bottom of the upper delivery conduit and the top of the lower delivery conduit for blowing the air on to the web, said nozzles being formed as transverse slots extending over the maximum width between the stenter guide rails and including side walls defining said nozzles and extending towards the web at an inclination thereto and leaving between the side walls transverse air escape channels extending widthwise over the guide rails at the maximum width spacing thereof.

3. A machine as claimed in claim 2, in which a proportion of fresh air is drawn into each fan through annular spaces around the motor and driving shaft thereby also cooling the motor.

4. A machine for air drying a web of material, including longitudinally extending stenter guide rails the width spacing between which is adjustable and between which the web is progressed through the machine; comprising in combination two inner air delivery conduits extending longitudinally one above and one below the web, two air return conduits extending longitudinally one on one outer side and the other on the other outer side of said delivery conduits, outer heat insulating conduit walls which enclose all said delivery and return conduits and define said delivery conduits, and longitudinal partition walls separating the return conduits from the delivery conduits and defining the return conduits, an electric motor and air delivery fan disposed transversely in the upper part of one return conduit and circulating air into the upper delivery conduit for delivery downwardly on to the top of the web and back over the web selvedge adjacent thereto, an electric motor and air delivery fan disposed transversely in the lower part of the other return conduit and circulating air into the lower delivery conduit for delivery upwardly onto the underside of the web and back across the web selvedge adjacent thereto, air heaters disposed longitudinally of said fans and on each side thereof in the respective return conduits, air passages through said partition walls adjacent the respective heaters allowing the air to pass from the web back through the heaters on each side of each fan for delivery to the delivery conduits, a series of air nozzles on the bottom of the upper delivery conduit and the top of the lower delivery conduit for blowing the air on to the web, said nozzles being formed as transverse slots extending over the maximum width between the stenter guide rails and including side walls defining said nozzles and extending towards the web at an inclination thereto and leaving between the side walls transverse air escape channels extending widthwise over the guide rails at the maximum width spacing thereof externally removable panelling on the outer heat insulating walls to enable easy access to be had to the return conduits, apertures in said partition walls allowing access from said return conduit to the guide rails.

5. A stenter machine for treating a web of cloth material, including longitudinally extending stenter guide rails the width between which is adjustable and between which the web is progressed through the machine; and comprising in combination two inner air delivery chambers extending longitudinally one above and one below the web, two air return conduits extending longitudinally one on one outer side and the other on the opposite outer side of said delivery chambers, outer heat insulating conduit walls which enclose all said delivery chambers and return conduits and form said return conduits, longitudinal partition walls separating vertically the return conduits from the delivery chambers, said walls forming a generally rectangular structure with rectangular cross section conduits and chambers, an electric motor and air delivery fan disposed transversely in the upper part of one return conduit and circulating air into the upper delivery chamber for delivery downwardly on to the top of the web and back over the web'selvedges adjacent thereto, an electric motor and air delivery fan disposed transversely in the lower part of the other return conduit and circulating air into the lower delivery chamber for delivery upwardly onto the underside of the web and back across the web selvedge adjacent thereto, said fans building up a positive pressure in said chambers, air heaters disposed longitudinally of said fans and on each side thereof in the respective return conduits, air passages through said partition walls adjacent the respective heaters and in line with the guide rails allowing the air to pass from the web back through the heaters on each side of each fan for delivery to the delivery chambers, a series of air nozzles on the bottom of the upper delivery chamber and the top of the lower delivery chamber for blowing the air on to the web, said nozzles being formed as transverse slots extending over the maximum width between the stenter guide rails and including side walls defining said nozzles and extending towards the web at an inclination thereto and leaving between the side walls transverlsge air escape channels extending over the guide ra KENNETH SOMERVILLE LAURIE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 

